1. Field of the Invention
The present invention relates to an image processing device, an image processing method, and a program.
2. Description of the Related Art
Conventionally, there are printing systems in which an external device such as a personal computer is connected to an image processing device through a wireless LAN or a wired LAN. External devices and image processing devices in a large number of printing systems operate as follows.
Specifically, the external device sends to the image processing device a print job that includes source data of a print image such as PDL (page description language) and print settings, and then the image processing device draws the print image according to the print settings and prints it on recording paper. When a failure occurs while the image processing device is processing the print job, a large number of image processing devices cancel the print job being processed.
However, when the cause of the failure can be removed, the printing processing may be able to be continued. Thus, there are proposed printing systems in which, when a failure occurs while an image processing device is processing a print job received from an external device, the image processing device stops the print job, and restarts the print job after the failure is resolved.
For example, Japanese Patent Laid-Open No. H08-293952 (1996) discloses how to cope with a situation where a facsimile starts receiving print data formed by an external device and then is powered off even while receiving the print data. After the facsimile is powered on again, a user selects, as a coping operation, one of operations of “redo”, “restart”, and “cancel” for send of the print data in the facsimile, and the facsimile performs processing in accordance with the selected operation.
As more and more external devices connected to image processing devices via networks are carried and the associated infrastructures are developed, printing systems have come to be widely used in which users traveling by foot, car, train and the like send a print job from an external device to the image processing device. However, in such cases, the networking is often interrupted by a factor on the side of the external device. Examples of the factor on the side of the external device include degraded radio condition of the network of the external device, a failure of an access point, the turning off of power, the suspending of the external device by the user and a lack of charge in the external device. As a result of this, the print job is often unsuccessfully completed. Thus, a printing system is required that stops the print job when the networking is interrupted by the factor on the side of the external device, and that can restart, after the network connection is achieved again, the print job from the state where the print job is stopped halfway through.
However, even a system disclosed in Japanese Patent Laid-Open No. H08-293952 (1996) is not capable of processing restart without involving a user. For this reason, in a conventional printing system, when the networking is interrupted by the factor on the side of the external device, an image processing device cancels a print job being processed. In order for the user to resend the print job, it is necessary for the user to confirm the reconnection of the network, specify the print job again and resend the print job as another print job; it is inconvenient, and needs time to resend the print job.
Meanwhile, if a network is interrupted while an image processing device is printing print data which are transmitted from an external device and have a setting such as stapling, punching or two-sided printing, the image processing device cannot process print data that are transmitted from another external device.
This problem occurs because a post-processing such as stapling or punching is performed after completion of print processing for the entire print data and a paper discharging process. Accordingly, if, while sheets of certain print data to be stapled or punched are being discharged to a paper tray, a sheet of other print data is discharged to the same paper tray, the sheets of the certain print data cannot be stapled or punched.
Meanwhile, in the case of two-sided printing, print processing is started after print data for a front face and a back face are received. Accordingly, the image processing device remains occupied if the network is interrupted when the image processing device only completes the reception of the print data for the front face. Hence the image processing device cannot process other print data.